East Brimfield Dam is on the Quinebaug River and covers an area of 2,070 acres in the towns of Sturbridge, Holland, and Brimfield, Massachusetts. The lake is part of a network of six flood control dams in the Thames River Basin constructed and maintained by the U.S. Army Corps of Engineers. Three of these projects, East Brimfield Lake, Westville Lake, and West Thompson Lake, help to control flooding from Sturbridge all the way to Long Island Sound.

The Corps regulates the flow of the Quinebaug River by raising or lowering two 6.5' x 11' electrically operated sluice gates in the gate house of East Brimfield Dam. The water flowing through this gate house drains an area of 67.5 square miles.

The Flood of 1955 caused much destruction in the Quinebaug River flood plain.

Total flood control storage at East Brimfield Lake amounts to 9,742,900 billion gallons (29,900 acre ft.) of flood waters at a maximum pool level of 32', (19' over normal pool level of 13'). Water from flood control storage is released after downstream river levels recede.

The Reservoir Regulation Team (RTT) at New England District Headquarters, in Concord, Massachusetts is the "nerve center" for New England flood control projects such as East Brimfield Lake. Using radio and satellite communications, the RRT constantly monitors river levels and weather conditions that influence flood control decisions.

East Brimfield Lake was placed into operation in June 1960 at a cost of $6,580,000. As of September 2009 it has prevented $109,144,000 in flood damages.